Radial piston pumps



United States Patent 3,516,334 RADIAL PISTON PUMPS Frank George Freeman, Solihull, England, assignor to Joseph Lucas (Industries) Limited, Birmingham, England Continuation-in-part of application Ser. No. 699,679, Jan. 22, 1968. This application Feb. 24, 1969, Ser. No. 801,479

Int. Cl. F04b 1/10, 49/00, 49/08 US. Cl. 91475 1 Claim ABSTRACT OF THE DISCLOSURE This application is a continuation-in-part of my patent application No. 699,679, and now abandoned. The invention relates to liquid pumps of the kind including a rotor supporting a plurality of radially reciprocable pistons, with the pistons engaging a surface which, for the purpose of pumping liquid, is eccentric with respect to the axis of rotation of the rotor, and the rotor being mounted within a body part in which are defined inlet and outlet ducts for the liquid.

The object of the present invention is to provide such a pump in a modified form.

In accordance with the present invention, a pump comprises a body part, an inlet and an outlet in the body part for liquid, a rotor mounted in the body part for rotation about an axis, a plurality of pistons occupying radially extending bores in the rotor respectively, a ring disposed within the body part, said ring providing an internal surface against which the outer ends of the pistons bear, biasing means acting between the body part and said ring, the biasing means urging the ring towards a position in which said surface thereon is eccentric with respect to the axis of rotation of the rotor, the body part having two spaced parallel flat surfaces which are inclined with respect to the direction of action of the biasing means, and the ring being capable of rolling on one of said surfaces as it moves in the body part.

The invention will now be described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a side elevation cross-sectional view of a pump constructed in accordance with the invention, and

FIG. 2 is a cross-sectional end elevation view of the pump.

The pump illustrated has a body part incorporating a detachable end cover 11 at one end. Within cavity 12 the body part is rotatably mounted a rotor 13. The rotor 13 has a plurality of radially extending bores 14 containing respective reciprocable pistons 15. Slippers 16 incorporated in the outer ends of the pistons bear against the internal surface of a ring 17 mounted in the body part 10. The internal surface of the ring 17 is part-spherical.

The rotor 13 has an integral tubular driving shaft 18 extending out of the body part 10 at its end remote from the end cover 11 and this shaft is mounted in a bearing 19 in the body part 10.

Acting against the ring 17 is a coiled compression spring 20 arranged to urge the ring 17 towards a position (illustrated) in which the ring and rotor are eccentric with respect to one another.

The side face of the rotor 13, adjacent to the end cover 11, is provided with a plurality of holes 21 communicating with the bores 14 respectively. The body part 10 has an inlet 22 for liquid to be pumped and the end cover 11 has an outlet 23.

Between the end cover 11 and the adjacent end of the rotor 13 is a part 24 in which is formed a kidney shaped port 25 affording communication between the holes 21 in the rotor 13 and the outlet 23.

The cavity 12 has two parallel wall portions 26, 27 against which the ring 17 bears, with the ring external surface contacting only one of these wall portions at any time, and the other portion acts as a guide for the ring 17. The ring 17, in use, rolls on one of said wall portions 26, 27. These portions 26, 27 are, moreover, inclined at an acute angle with respect to the axis of the spring 20 as shown. The spring 20 is mounted in the body with substantial clearance to permit some distortion during rolling motion of the ring 17 relatively to the appropriate wall portion of the body cavity.

In use, there exists a force which is the resultant of the forces applied by the pistons 15 on the ring 17, with this resultant force tending to move the ring towards a position in which the ring 17 and rotor 13 have their axes substantially coincident. Movement under the action of this force takes place against the spring 20 and only occurs when the value of the force in the plane of the spring axis exceeds the spring rating. The planes of the portions 26, 27 of the cavity wall are also inclined to the direction of action of the resultant force.

The wall portions 26, 27 are so disposed that the ring 17 can occupy a position in which the ring 17 and rotor 13 have their axes coincident.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A radial piston type pump comprising a body part, an inlet and an outlet in the body part for liquid, a rotor mounted in the body part for rotation about an axis, said rotor having radially extending bores, a plurality of pistons occupying said radially extending bores in the rotor respectively, a ring disposed within the body part, said ring having an internal surface against which the outer ends of the pistons bear, spring means operative between the body part and said ring for urging the ring towards a position in which said surface is eccentric with respect to the axis of rotation of the rotor, and the body part having two spaced apart parallel flat surfaces which are inclined at an acute angle with respect to the axis of the spring means, with the ring being capable of rolling on one of said parallel flat surfaces as it moves in the body part.

References Cited UNITED STATES PATENTS 2,293,692 8/1942 Wylie 103161 2,429,011 10/ 1947 Wylie 103161 2,518,578 8/1950 Tomlinson 10316l 2,716,945 9/ 1955 Presnell 103161 2,871,797 2/1959 Bourassa et a1.

3,096,723 7/ 1963 Puryear.

3,097,607 7/ 1963 Freeman.

WILLIAM L. FREEH, Primary Examiner US. Cl. X.R. 417219 

